fix(module:slider): drag, select, focus and rapid reposition fix

[anddrzejb]

🤔 This is a ...

• New feature
• Bug fix
• Site / documentation update
• Demo update
• Component style update
• Bundle size optimization
• Performance optimization
• Refactoring
• Code style optimization
• Test Case
• Branch merge
• Other (about what?)

🔗 Related issue link

This addresses a number of small issues with slider:

1. When clicked and dragged to the left, often before first movement to the left a movement to the right was executed:
   

2. When dragging, especially after page load, nothing was happening:
   

3. For ranged slider, when dragging one edge beyond the other range, the focus was not following (I am referring to transparent gradient border that is showing when edge gets focus) :
   

4. For ranged slider, when quickly dragging one edge beyond the other edge, the "not changed" edge also moves:
   

5. When dragging an edge, text selection should be inactive:
   

💡 Background and solution

1. Required changes to calculation method of the edge position.
2. Previously added method IsMoveInEdgeBoundary was removed from OnMouseMove event handler.
3. When side switch is discovered, a js focus method is called on appropriate edge.
4. When ranged slider is used, original values of each edge are stored when mouse down is registered. During side switch, the stored values are persisted, to ensure they do not change.
5. Added to class @{slider-prefix-cls} css user-select:none

📝 Changelog

Language	Changelog
🇺🇸 English
🇨🇳 Chinese

☑️ Self Check before Merge

⚠️ Please check all items below before review. ⚠️

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• Changelog is provided or not needed

[codecov-io]

Codecov Report

Merging #903 (fd519c5) into master (3f8a5a7) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@            Coverage Diff            @@
##           master    #903      +/-   ##
=========================================
- Coverage    5.55%   5.54%   -0.02%     
=========================================
  Files         400     400              
  Lines       21300   21331      +31     
=========================================
- Hits         1184    1182       -2     
- Misses      20116   20149      +33     

Impacted Files	Coverage Δ
components/slider/Slider.razor	0.00% <0.00%> (ø)
components/slider/Slider.razor.cs	0.00% <0.00%> (ø)
components/tabs/Tabs.razor.cs	55.51% <0.00%> (-0.82%)	⬇️
components/input/Input.cs	0.00% <0.00%> (ø)

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[ElderJames]

Thank you @anddrzejb for the great contribution.
Everything is good but the style changing is not a good idea, because the styles are synchronized from the ant-design.
So it's best to go there repo and fix the style.

[anddrzejb]

So I see 1 option then: hard code it in the slider div in the style attribute. Do you agree @ElderJames ?

[ElderJames]

So I see 1 option then: hard code it in the slider div in the style attribute. Do you agree @ElderJames ?

@anddrzejb It's OK.